Depends on what their shtick is. People with a fun personality bringing attention to games worth knowing about, sharing their gaming stories, spreading the word about new games, providing worthwhile reviews to help people decide if a game is worth buying...all good things, but as Hammerfestus said, you have to stand out to justify entering an already saturated market. We have enough people with blasé personalities whose videos boil down to "I like games, I am going to show you games." Either be a personality/character that makes you worth watching, or have a depth of knowledge that rises above more superficial content. Also, if successful, they also need to be able to recognize when they have nothing more to contribute and it's time to stop making content or else risk damaging your legacy.